American Sign Language: "fiction"

The concept of "fiction" is expressed by using the sign for FALSE.
To do the sign for "false," or "fiction" -- move your "index finger"
past your nose. Your index finger doesn't touch the nose, it just
comes close. The movement can be in the wrist or it can be more in the elbow
as I show here. The movement is NOT in the knuckle.

FICTION (false + context)

You could also use the "INVENT" sign to mean "fiction." (As in, an
invented story rather than a "true" one.) See:
INVENT